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What is the rarest Tourmaline?
The rarest Tourmaline is called Paraiba. Along with being the rarest, it is also the most expensive. We only come across great Paraiba one every few years. The easiest way to see if a Tourmaline is Paraiba is by the neon-like blue and green with traces of copper.
What colors is Tourmaline available in?
Tourmaline is a gemstone that is available in many, many different colors. From black to deeper browns, to yellow, to blue, to green, to red, to yellow, to pink. Some Tourmaline can even be found colorless. And even better yet, you can find Tourmaline that have many different colors in one gemstone!
Tourmaline price per carat?
This is a tougher question, as it really depends on the color and clarity of the gemstone. With so many colors available in Tourmaline, you can find it at $50 a carat, or more rare Tourmaline can fetch up to $10,000 per carat. True Brazilian Paraiba can hit $50000 per carat
How do you determine the value of Tourmaline? Can these be very expensive?
Value is market driven and changes often. We check prices at trade shows and use the publication “The Gem Guide” which gives wholesale pricing also from worldwide trade shows. Prices of tourmalines are generally under $500 per carat but in the case of Paraiba can reach $50000 per carat.
Where is Tourmaline found?
Tourmaline can be found all around the world. Some popular areas are Afghanistan, Pakistan, Russia, Burma (Myanmar), Sri Lanka (Ceylon), and the United States (California and Maine). If you are traveling to Africa, these African countries also have Tourmaline: Madagascar, Namibia, Mozambique, Tanzania, Nigeria, and Malawi. Steve has traveled quite a bit to Madagascar and Tanzania. Congo is the newest source for fine Tourmalines.
Is Tourmaline a Quartz? Why?
Tourmaline is unrelated to quartz. All characteristics are different from quartz.
What is the refractive index of Tourmaline?
The refractive index of tourmaline lies between 1.624 and 1.644.
What are the main properties of Tourmaline?
What is the hardness or mohs scale for Tourmaline? How durable is it?
It has a rating of 7-7.5. The higher the value, the harder the stone. With this level, Tourmaline is durable and can be worn in rings, pendants, bracelets and earrings with very few issues.
What is Paraiba Tourmaline?
This is the rarest of all Tourmaline. Neon-like blue and green with traces of copper. It is the incandescent glow that appears to light up the stone that makes this stone very popular, but also very rare. It can be up to $50,000 per carat, depending on the quality and size. Traditionally, this stone has come from Paraiba, Brazil. In recent years, discoveries have been made in Mozambique and Nigeria in Africa known as Cuprian Tourmaline. The value of Cuprian tourmaline is significantly less than Paraiba but still can command prices over $10000 per carat.
What are the healing properties?
Looking at Chakras, Tourmaline energizes and balances Chakras. This can be slightly different depending on the color of the stone. For healing, Tourmaline is great for weight loss. It should be incorporated into one’s clothing. Unfortunately, there are so many uses for Tourmaline, due to the different colors. We highly recommend reviewing Healing with Crystals for a deep look into each.
Tourmaline vs Emerald? Difference?
The closest tourmaline in color to emerald is chrome tourmaline. Both emerald and tourmaline are colored by chromium. Chrome tourmaline is often of higher clarity than emerald but unlike emerald chrome tourmaline is often darker in color than emerald and can be overly dark. The finest chrome tourmalines have a beauty that can outshine most emeralds and are rarer than emerald as the only source is Tanzania.
Tourmaline vs Sapphire? Difference?
Hardness and refractive index are there greatest differences. Both come in a myriad of colors that can look similar but to the trained eye the look of each is different.
What is the birthstone month?
Tourmaline is commonly the birthstone for October. The generally accepted color for the birthstone is Pink Tourmaline.
How do you identify a Tourmaline gemstone?
Refractive index and strong birefringence is the easiest separation. The dicroscope is helpful as the pleocroic colors are dramatic. Rough crystals are often long and pencil like with line
Can Tourmaline crack or break easily?
It has a 7-7.5 on the Mohs scale so it won’t break easily. But there are areas of tension within Tourmaline that can cause it to crack, but this is mainly when jewelers are working on the store or setting it. Not common with every day use.
Can Tourmaline get wet?
Water has no effect on tourmaline.
Can Tourmaline be heated?
Many are heated to alter the color but it needs to be done slowly. Inclusions within the stone can cause damage when heating.
Can Tourmaline be tumbled?
Yes
Is Tourmaline ever treated?
Heating is the most common but some material particularly Brazillian rubellites are irradiated to alter color.
Can Tourmaline fade?
Fading only occurs with high temperature and is often used to improve the color of overly dark tourmalines. They do not fade under normal wear.
Can Tourmaline be white? Blue?
Yes, Tourmaline can be found in blue known as indicolite tourmaline, The blue is also seen in Pariaba Tourmaline. It’s more of a neon green-blue color. While white is not available tourmaline can be found to be clear known as acroite tourmaline.
What color Tourmaline is best? Worst?
Paraiba is the most valuable but what is best is a personal thing. Each color has a more desirable shade with the least value being those that are over dark and secondary shades like browns which sometimes detracts from the beauty as in pink tourmalines.
How is Tourmaline formed?
Tourmaline is produced in pegmatites. When the liquids begin to cool, the minerals crystallize and form Tourmaline crystals.
How do you clean Tourmaline?
Generally a soft brush and mild detergent is best. Many will be ok in an ultrasonic cleaner if cool but there is still some risk. Steam cleaning should never be used.
When was Tourmaline first discovered?
While the exact date is known. It is believed that the conquistadors in Brazil first discovered Tourmaline in the 1500’s. What was discovered were green Tourmalines, which they actually thought we Emeralds. It wasn’t until the 1800’s that scientists figured out that these stones were not actually Emeralds, but their own species of mineral, which they called Tourmaline.
Who discovered Tourmaline
It is believed that the conquistadors in Brazil were the first ones to discover Tourmaline.
Why is watermelon Tourmaline so expensive?
Rarity and high demand make this unique gem so valuable. Few gems have such a distinct character. Watermelon in the trade are the slices that look like a watermelon slice with a green rind and pink center. Most in the public also think of bi-color and tri-color tourmalines as watermelon. These are generally long pencil shape faceted bars with one end green and one end red with some having a clear or yellow center.
Is green Tourmaline rare? Can it be expensive?
Green tourmaline is most expensive when it has some blue in it or appears more like emerald as in the Chrome Tourmaline.
How do you tell if Tourmaline is real vs fake?
I have seen a few fakes which were hard to believe they were fake because tourmaline has such a distinct look, particularly greens and blues. Gemological testing for refractive index and birefringence is the best separation.
What makes Tourmaline a certain color?
The amount of manganese and copper cause the different colors in Tourmaline.
Is Tourmaline a good investment stone?
Tourmaline has great beauty and is in high demand so if you can buy high quality at a good price it has potential as an investment. Look for new discoveries that for a short period are often seen at lower prices due to large supply.
Is pink tourmaline the same as rubellite?
Once pink looks red it is rubellite. Most rubellite will have some violet or pink color highlights but you should look at it and the best description should be red. G.I.A states that it could have brownish, orangy or purplish secondary colors.
Is Tourmaline considered a precious gemstone?
Yes tourmaline is precious,at up to $50000 per carat it is what I would consider precious. The terms precious and semi-precious have lost their meaning in today’s gem market.
Is Tourmaline Magnetic?
Some tourmalines are magnetic particularly those with high concentrations of iron. Of the rough tourmalines that I have in stock I cannot detect any magnetism. They do carry an electrical charge and if you leave tourmalines in place for a long term they tend to develop a ring of dust around them.
Does Tourmaline have pleochroism?
Toumalines are strongly pleochroic with dramatic color differences when viewed with a dicroscope.
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Questions? Ask the expert and owner, Steve Moriarty. He has over 40 year experience in the industry. GIA certified gemologist. Learn more about Steve Moriarty here.
Tourmaline is a name applied to a family of related minerals with widely varying properties. Tourmalines make very popular jewelry stones and come in an amazing range of colors, including multi-color zones. Tourmaline is the modern October birthstone, and pink in particular is a very popular color.
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Tourmalines: worldwide sources, color suite (from 3 to 12 cts). Photo © Joel E. Arem, PhD, FGA. Used with permission.Tourmaline is a mineral supergroup that consists of three groups, multiple subgroups, and over thirty different species. With new discoveries, the list of tourmaline species continues to grow. They all have the same trigonal (hexagonal) crystal structure but different chemical formulas.
The Victorian writer John Ruskin's quip from 1890 still applies to tourmalines today:
The chemistry of [tourmaline] is more like a medieval doctor's prescription than the making of a respectable mineral.
The basic formula is:
XY3Z6(T6O18)(BO3)3V3W
X, Y, Z, T, V, and W can represent different elements, so many substitutions and, hence, variations are possible. This chemical complexity can create a vast array of appealing colors in tourmalines, including multi-color patterns.
A custom shield-cut tourmaline with a pink-and-yellow bi-color combination. 1.50 cts, 10.4 x 7.8 mm, Nigeria. © The Gem Trader. Used with permission.Tourmaline colors can satisfy just about any fashion requirement. With a hardness of 7 to 7.5, no cleavage, and only slight brittleness, these gems make excellent jewelry stones for everyday wear.
Tourmaline and diamond jewelry. Photo © Joel E. Arem, PhD, FGA. Used with permission.In addition, tourmaline crystals occur in abundance worldwide, often cuttable and sometimes large and well-terminated. These factors keep tourmalines priced low in general and highly popular with consumers.
A Celtic-inspired ring with a deep green tourmaline (pear cut) surrounded by white opal accents. Photo by CustomMade. Used with permission.Tourmalines are also suitable for carving cameos and intaglios as well as all manner of shapes and figures.
All members of the tourmaline supergroup are considered tourmalines. The properties of some species are so close that separating them proves difficult. For gemological purposes, it's sufficient to identify them all as tourmaline.
Distinguishing tourmalines into specific species may require advanced gemological tests, like laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS).
Tourmalines are piezoelectric as well as pyroelectric. They generate electricity when placed under pressure and heated, respectively. They also generate an electrostatic charge when rubbed.
Tourmalines come in all colors, from colorless to black. Crystals are frequently color zoned along their length (bi-color, tri-color, parti-color, and so forth) or concentrically zoned (watermelon tourmaline).
The vast majority of cut tourmaline gemstones belong to the elbaite species. Other species you might find cut or in jewelry are dravite, liddicoatite, schorl, and uvite. You'll rarely encounter other tourmaline species cut as gemstones, but they do show up occasionally.
The following table breaks down the difference in optical and physical properties between various species. (Note that all tourmalines have the same optic character and dispersion. Hardness can vary from 7 to 7.5). The species most commonly encountered as gemstones are listed in bold italic type.
Although you might find specimens described as buergerite, the correct name for this tourmaline species is fluor-buergerite. The "W" site in its chemical formula is fluorine (F). ("Buergerite," with oxygen-hydrogen (OH) in the "W" site, has not been found).
These rare, dark brown to black crystals may have a bronze-colored iridescence under the surface.
Chocolate brown buergerite crystals on matrix. 5.3 x 4.3 x 1.7 cm, Mexquitic, San Luis Potosí, Mexico. © Rob Lavinsky, www.iRocks.com. Used with permission.Also known as chromium-dravite or chromian dravite, this is a chromium-rich (Cr) dravite variety. This tourmaline has an intense, dark green color.
Dravite colors can vary, from yellow, brown, black, and greenish black to dark red, pale blueish green to emerald green, and even colorless. It has many sources.
The most common tourmaline species, elbaite comes in all colors from many sources.
Elbaite crystals in various colors, including bi-color. 1.4 x 0.4 x 0.4 cm, 2.5 x 0.5 x 0.5 cm, 2.5 x 0.2 x 0.1 cm, 1.6 x 0.4 x 0.4 cm. Konar Province, Afghanistan. © Rob Lavinsky, www.iRocks.com. Used with permission.The rare, dark brown to black iron member of the uvite subgroup.
A bluish black to dark indigo tourmaline with purple tints.
Foitite crystal from Mt. Mica, Maine. The backlighting highlights its purple tints. © Rob Lavinsky, www.iRocks.com. Used with permission.
Although the name refers to tourmalines with complex, multi-colored zoning, these stones may belong to two species. For years, scientists believed liddicoatite was a type of elbaite. In 1977, it was determined to be a calcium analogue to elbaite (with Ca in the "X" site). Years later, liddicoatite was redefined. Fluor-liddicoatite is F-dominant ("W" site), while liddicoatite is OH-dominant ("W" site). Investigations to determine if OH-dominant liddicoatite exists in nature continue. For now, it's not an approved species name. However, the term "liddicoatite" is still popularly used to refer to stones that are actually fluor-liddicoatites.
This liddicoatite slice shows green, yellow, grayish blue, and pink zones, with a purplish pink center and a triangular core. 15.96 cts, 30.1 x 25.3 x 2 mm, Alakamisy Itenina, Fianarantosa, Madagascar. © The Gem Trader. Used with permission.Magnesium-dominant (Mg in the "Y" site) foitite with greenish brown to blueish gray color.
Tourmaline with colors ranging from blue to pale shades of pink, blue, or green, as well as colorless.
In 1997, researchers determined this rare tourmaline, formerly known as ferridravite, was not actually the ferric (Fe3+) analogue of dravite. It has a nearly opaque, dark brown, brownish black, or black color.
A rare, pink to tan tourmaline.
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Black schorl has been used in jewelry since ancient times. During the Victorian Era, schorl frequently appeared in mourning jewelry. In modern times, this common tourmaline is seldom cut into gemstones. Schorl also occurs in brown, blue, or blue-green shades.
Gold ring with an intaglio of the mythological Daedalus carved into a schorl stone. Roman, 3rd century CE. Photo courtesy of liveauctioneers.com and TimeLine Auctions Ltd.Tsilaisite was first proposed as a name for a hypothesized manganese-dominant (Mn) tourmaline species in 1929. In the mid-1980s, discoveries in Zambia of yellow tourmalines with high Mn content prompted some researchers to assert these were natural tsilaisites. Vendors even began using this name, despite it being unapproved and the stones falling short of the criteria for a new species. In 2006, researchers determined these stones were only Mn-rich elbaites and discredited the name. When tested in 2011, more than 200 candidate stones from all over the world failed to have the Mn content (>10.71 wt.% MnO) required for classification as tsilaisites.
However, in 2012, yellow tourmalines discovered in Elba, Italy proved to be the elusive Mn-dominant species (with Mn in the "Y" site). Thus, the tsilaisite species was finally officially approved.
Yellow, Mn-rich tourmalines from all over the world, like this 7.07-ct. oval-cut gem from Madagascar, have been called tsilaisites. However, they don't have the necessary chemical composition to qualify as examples of this distinct species. © The Gem Trader. Used with permission.Another revised and re-approved species (in 2020), uvites form a tourmaline subgroup, consisting of uvite proper, fluor-uvite, and feruvite. Most uvite specimens are actually fluor-uvite, the common, F-dominant member (with F in the "W" site).
Uvites have a wide range of colors: black, light to dark green, brown, red, and occasionally other colors, including colorless.
A vanadium-bearing dravite with dark green to black color.
Vanadium-rich chrome dravite, 2.7 x 2.1 x 1.4 cm, Pyant Gyi mine, Mogok Township, Mandalay, Myanmar. © Rob Lavinsky, www.iRocks.com. Used with permission.There are many trade names for tourmalines, based on their color and appearance. Though their characteristics may coincide with those of specific species, the following are not species names. For example, rubellites are typically elbaites but may also be liddicoatites and olenites. Paraíba tourmalines were long thought to be exclusively elbaites, until copper-bearing liddicoatites with paraíba colors were identified in 2017.
Although an official species, the dravite name is sometimes applied to yellow and brown tourmalines, even if they don't belong to that species.
Colorless tourmalines.
1.43-ct achroite, Madagascar. Photo courtesy of liveauctioneers.com and Jasper52.Bright yellow tourmalines.
Canary tourmalines, matched pair, square radiant cut, Zambia. Heat treated. © The Gem Trader. Used with permission.Cat's eye tourmaline: Brazil (20.85). Photo © Joel E. Arem, PhD, FGA. Used with permission.Chatoyant tourmalines in a variety of colors.
Colored by chromium or vanadium, these stones exhibit an intense green color. Tourmalines colored green without chromium or vanadium are called verdelites.
Extremely rare tourmalines that show a distinct color change, from daylight to incandescent light
Some tourmalines can show an Usambara effect, a type of color change that depends, in part, on the lengths of the path of light through the stone.
4.57-ct color-change tourmaline, dark green to reddish brown, mixed marquise cut, East Africa. © The Gem Trader. Used with permission.
Blue tourmalines. Stones with intense, neon-blue colors caused by copper are called paraíba tourmalines.
9.84-ct, emerald-cut indicolite, Brazil. A pure, dark blue body color with indigo-colored ends. Photo © Joel E. Arem, PhD, FGA. Used with permission.Intense, neon-blue tourmalines colored by copper. Originally discovered in and named after the Brazilian state of Paraíba, specimens have also been found in Nigeria and Mozambique. The gem community largely accepts the definition of paraíba tourmalines by color and copper content. However, you might find some dealers reserve the term for the Brazilian material, referring to the African material as "paraíba-like" or just cuprian blue tourmaline.
Identifying the source of paraíba tourmalines requires a LA-ICP-MS test for quantitative chemical analysis.
Paraíba tourmaline, oval modified brilliant cut, 16.33 cts, 18.02 x 14.89 x 8.04 mm, Brazil. Photo courtesy of liveauctioneers.com and Kissing Auction.Tourmalines with blue colors not caused by copper are called indicolites.
Tourmalines that have more than one color.
The term rubellite typically refers to tourmaline with reasonably saturated dark pink to red colors and medium to dark tones, from raspberry to ruby-like red. These stones are often strongly purplish, orangish, or brownish.
Pala, California (15), Brazil (22, 18), Pala (26), Africa (11) // Pala (4), Brazil (5), Africa (8), Brazil (4, 4). Photo © Joel E. Arem, PhD, FGA. Used with permission.When sliced perpendicular to the c axis, trapiche tourmalines show inclusions formed from organic matter between growth sectors of its crystal structure, which resemble spokes radiating from the center of a wheel. Though these patterns may appear star-like, these aren't star stones.
Polished trapiche tourmaline slice, 6.95 cts, 14.9 x 12.4 mm, Zambia. © The Gem Trader. Used with permission.Green tourmalines. Stones with deep green color caused by chromium or vanadium are considered chrome tourmalines.
3.04-ct, round-cut verdelite. Photo courtesy of liveauctioneers.com and Jasper52.Tourmalines with a pink or red "core" or center and a green "rind" or border. Some specimens have a colorless ring between these two areas. When cut, these stones resemble slices of watermelon.
Watermelon tourmalines, Brazil (large slice, approximately 1" across). Photo © Joel E. Arem, PhD, FGA. Used with permission.Although tourmalines are popular gems, other gem names may have more caché and command higher prices. As a result, some unscrupulous vendors might use evocative but deceptive combinations of gem names to sell tourmalines more easily. For example, you might encounter green tourmalines sold as "Brazilian emeralds" or "Ceylonese peridots" and blue tourmalines sold as "Brazilian sapphires."
These terms are not acceptable trade names for tourmalines. Of course, tourmalines, emeralds, peridots, and sapphires are all distinct gem species. Emeralds and sapphires are also quite a bit more expensive than most tourmalines. To complicate matters, emeralds really do occur in Brazil, and peridots do occur in Sri Lanka. Ask vendors to clarify the names and sources of any tourmalines they sell or ask for a gem lab analysis, especially for any high-value gemstones.
Dark green and brown tourmalines display especially strong pleochroism, while pale colors have weak dichroism. Light traveling along the length of a prismatic crystal always shows a deeper color than at right angles to this direction.
This dichroic, rectangle-cut tourmaline looks forest green when viewed face up but olive green from the sides. © Rob Lavinsky, www.iRocks.com. Used with permission.
The absorption of the o-ray in tourmaline is strong enough to plane-polarize light. Sometimes, this ray is totally absorbed and a tourmaline may appearisotropic, because it shows only one absorption edge on the refractometer.
Most tourmalines fall under the Type II clarity category, "Usually Included." Green tourmalines are Type I, "Usually Eye Clean," while red and watermelon tourmalines are Type III, "Almost Always Included."
This 4.82-ct pink tourmaline from the Stewart Lithia Mine in California has visible inclusions. © All That Glitters. Used with permission.All tourmalines may contain inclusions of hollow tubes — elongated or irregular thread-like cavities, sometimes with liquid or gas inclusions, sometimes two-phase inclusions — often in mesh-like patterns. The tubes usually run parallel to the length of crystals and, when densely packed, may produce a chatoyant effect in cabochons.
Red tourmalines may contain gas-filled fractures as well as flat films that reflect light and appear black.
Tourmalines may contain mineral inclusions of hornblende, mica crystals, apatite, and zircon.
The copper inclusions in this rectangular step-cut tourmaline create a schiller effect. 4.48 cts, 19 x 6.3 mm, Brazil. © The Gem Trader. Used with permission.Some clear quartz stones may contain needle-like inclusions of black tourmaline crystals. Referred to as tourmalinated quartz, these pieces can make attractive display crystals as well as intriguing gemstones for jewelry.
Scientists have produced synthetic tourmalines for research purposes. For example, before the discovery of tsilaisite in nature, researchers had produced it the laboratory (1984) as well as other Mn-rich tourmalines (2003). With that in mind, is there any lab-created tourmaline commercially available for gem or jewelry use? The answer is no.
In 1993, Russian scientists synthesized tourmalines via a hydrothermal process. In this case, synthetic tourmaline was grown over natural tourmaline seed crystals. Curiously, in 2008, the International School of Gemology (ISG) — not the International Gem Society (IGS) — concluded that some unusual tourmalines it acquired were most likely synthetics manufactured like those in the 1993 experiment. As the news of that declaration spread, so did rumors that these synthetics had entered the gem market.
Bear Williams of Stone Group Labs debunked that rumor. In his 2009 article, he wrote that the 1993 experiment only produced a minuscule amount of synthetic tourmaline at great cost. Furthermore, he noted that the ISG had made errors comparing the Raman spectroscopy of its specimens to those examined during the 1993 research. (In a response, the ISG reported that it reevaluated its tourmaline specimens and determined they were actually natural liddicoatites, not synthetics).
Synthetic tourmaline is expensive and difficult to create. Furthermore, there's no economic motive to synthesize this material for commercial use. Inexpensive yet gem-quality natural tourmalines are readily available. Although you can find so-called "synthetic tourmaline" for sale online, careful reading will reveal the term is usually used synonymously with "fake" or "simulated." If the simulant is a lab-created material, vendors may claim the "tourmaline" itself is, thus, lab-created. In actuality, it's not a tourmaline at all.
On the other hand, tourmalines can receive many enhancements. These can easily improve a low-quality stone's appearance and color as well as change its natural color into something more attractive (and valuable).
The following sources are some of the major producers of tourmalines, and the varieties listed are some of the most notable from those sources. Many listed sources also produce additional varieties of tourmalines. Many other sources not listed also produce tourmalines.
Tri-color tourmaline rough from Nigeria. © Dan Stair Custom Gemstones. Used with permission.At Nuristan, superb gem elbaite in shades of blue, pink, green, and even emerald green.
Greenish blue tourmaline, square cushion with checkerboard top, 2.09 cts, 7.5 mm, Afghanistan. © The Gem Trader. Used with permission.At Cochabamba, povondraite.
In Minas Gerais and other states, usually elbaite, in a huge variety of colors and sometimes large crystals; also bi-color, cat's eye, watermelon tourmaline. Especially noteworthy are the immense cranberry-red crystals from the Jonas Lima Mine and the superb dark-red material from Ouro Fino.
At Strázek Moldanubicum, rossmanite.
At Kashmir, green elbaite crystals. RI 1.643, 1.622; SG = 3.05, birefringence = 0.021.
At Honshu, magnesio-foitite, rare.
Fine, deep red and other colors. The red is dravite; (also yellow shades). The following table describes their properties.
e
o
Birefringence
SG
Color
1.623
1.654
0.031
3.07
red
1.626
1.657
0.031
3.08
red
1.619
1.642
0.022
3.04
yellow
Canary tourmalines.
Liddicoatite (previously thought to be elbaite) in a huge range of colors, shades; crystals often concentrically zoned with many color zones, triangular in outline; many crystals very large. Also, fine rubellite.
Buergerite occurs in rhyolite at San Luis Potosí, rare.
Paraíba (cuprian) tourmalines. At Alta Ligonha, pale-colored elbaite in various shades; bi-colors.
Round brilliant-cut pink tourmaline, 4.44 cts, faceted from material mined in Mozambique in 1972. Photo © Joel E. Arem, PhD, FGA. Used with permission.The Mogok area produces red tourmalines, also some pink elbaites and brown uvites.
Feruvite found at Cuvier Island, rare.
Paraíba (cuprian) tourmalines and other varieties.
5.46-ct, hot pink tourmaline, Nigeria. "RS Brilliant" cut by Loren Brown. © RSA Gems. Used with permission.At Glenbuchat, Aberdeenshire, color-zoned elbaite up to several centimeters, suitable for cutting.
Yellow and brown crystals. This is an ancient source of gem tourmaline, now known to be uvite rather than dravite.
Elbaite containing Cr and V, resulting in rich green shades.
Rectangular step-cut chrome tourmaline, 3.02 cts, 10.6 x 6.5 mm, Tanzania. © The Gem Trader. Used with permission.At Chipata, dark red crystals similar to Kenyan dravite. RI 1.624-1.654; birefringence = 0.030; SG = 3.03-3.07 (average 3.05). Also gemmy yellow material with up to 9.2 wt. % MnO, very rare. Also, trapiche tourmalines.
Elbaite with light pink and yellow or green colors, depending on the viewing angle. 5.49 cts, 10.2 x 10.2 x 8.5 mm, Zambia. "Hexact" cut by Loren Brown. © RSA Gems. Used with permission.In the Somabula Forest area, fine elbaite.
Tourmalines weighing hundreds of carats have been cut out of material from various localities. Brazil and Mozambique produce some of the largest stones, but Maine and California have also yielded crystals of very large size. Most larger museums have fine tourmaline collections and display very large gems. (A representative collection of tourmaline colors would have to encompass well over 100 stones).
Tourmaline rough can challenge even experienced gem cutters. Multi-colored gems are often weak where the colors meet, but all color varieties may have stressed areas. Nevertheless, once cut and set in jewelry, tourmalines are very durable stones.
Tourmaline's Mohs hardness of 7 to 7.5 means these gems can resist scratches from most everyday hazards, including household dust. That's very fortunate, because due to tourmaline's electrical conductivity, these gems will attract more dust than non-conductive stones. So, you may have to clean them frequently
Since most tourmalines have numerous inclusions, avoid cleaning them with ultrasonic or steam devices. Vibrations and heat may cause liquid inclusions to expand, shattering the stone. Instead, use a soft brush, mild detergent, and warm water.
Consult our gemstone jewelry care guide for more recommendations.
Contact us to discuss your requirements of Sillimanite powder for ceramic insulation materials. Our experienced sales team can help you identify the options that best suit your needs.
Hand-wrought, 14k gold ring featuring a tourmaline slice. Photo courtesy of liveauctioneers.com and Nest Egg Auctions.